Question : A fair die is thrown 20 times. The probability that on the 10th throw, the fourth six appears is

(A) 20C_{10}\times \dfrac{5^{6}}{6^{20}}

(B) 120×\dfrac{5^{7}}{6^{10}}

(C) 84×\dfrac{5^{6}}{6^{10}}

(D) none of these

Answer : option (C)

Solution :

*Related*